Rotary printing press



Sept. 21, i943. c. s. CRAFTS ROTARY PRNTING PRESS Filed oct. 24, 1940 :s sheets-sheet 1 VENTOR Sept. 21, 1943. c. s. CRAFTS ROTARY PRINTING PRESS Filed Oct. 24, 1940 5 Sheets-Sheet 2 VENTOR Sept. 21, 1943. c, s, CRAFTS ROTARY PRINTING PRESS Filed Oct. 24, 1940 3 Sheets-Sheet 3 Patented Sept. 21, 1943 UNITED STATES PATENTDF'FICE ROTARY PRINTING PRESS Curtis S. Crafts. Oak Park, Ill., assignor to The Goss Printing Press Company, Chicago, Ill., a corporation of Illinois' i Application october 24. 1940, serial No. 362,518

Claims.

The present invention relates to new and useful v improvements in the impression cylinders of rotary printing presses, andA more particularly to th'e impression cylinders v"of relatively large multicolor magazine printing presses.

Objects and advantages of the invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practice with the invention, the. same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims.

(Cl. lol-415.1)

, end of one or more of the underlying sheets of The invention consists in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate one embodiment of the invention, and together with the description, serveto'explain the principles of the invention.

0f the drawings:

Figure l is a fragmentary end elevation, with 'f certain parts broken away, of a typical and illustrative embodiment of the present invention;

Figure 2 is a fragmentary radial sectional view of the tympan holding and stretching means at'Y packing unattached, means being provided for stretching Ithe outermost, and generally the innermost, sheets of packing material. In this way, the intermediate sheet of packing, which' is frequently a softer and more resilient grade of paper, is left .relatively free at its trailing edge and is held in position by the binding actionof the outermost sheet of packing and the friction of this intermediate sheet against the innermost sheet of packing.

lIn the operation of a multicolor rotary web printing press utilizing such conventional form of impression cylinder, and particularly where the impression cylinder is three or four times the Figure 4 is a fragmentary end view' with certain parts broken away, and showing the tympan' sheet holding and stretching means of the illustrative impression cylinder;

Figure 5 is a fragmentary sectional view of an impression cylinder in accordance with the present invention showing the manner in which the tympan sheets are clamped and stretched, a'nd their operation with a printing cylinder; and

Figure 6 is a fragmentary diagrammatic sectional view showing the manner in which a wrinkle forms in the tympan on the impression cylinder of a conventional printing press.

In multicolor rotary web printing presses such as are commonly used for the high speed printing of magazines, it is customary to have an impression cylinder which has a diameter considerably larger than the diameter -of the several plate cylinders with which it cooperates. Such an impression cylinder is conventionally covered with a plurality of thicknesses of relatively hard but slightly resilient packingsuch' as oiled manila paper, and these sheets of packing are removably secured so as to cover the entire surface of the diameter of the printing cylinder, there is a decided tendency on th'e part of the underlying sheets to creep, and when this creeping has progressed sumcientlyfar, a wrinkle occurs in the packing ofthe impression cylinder which spoils the I printed product, injures the plates on the printing cylinder, and if allowed to continue will break the printing plates and thereby result in damage to the press and possible injury to the pressman. v

v The present invention has for its object the provision of anovel and improved impression cylinder which avoids these defects of the prior art and can be safely operated for long periods of time with'out injury to the packing or the printing plates land produces a superior quality of printing. The invention also provides an improved tympan clamping and stretching means which will hold all of the sheets of packing on the impression cylinder without wrinkling.

In accordance with the present invention, the several sheets of packing or other material with which the impression cylinder is clothed are securely clamped to the impression cylinder along the trailing edge of these sheet s,and at least the outer, and preferably the innermost, sheets of packing are secured at their leading edges by means which allow the outer and innermost sheets to be maintained taut, the intermediate sheets of packing being clamped to the cylinder" at their leading edge except for 'the binding action of the outermost sheet and the friction between the intermediate sheet and the other packing sheets.

It will be understood that the foregoing general description and the following detailed description as well, are exemplary and explanatory of the invention but are not restrictive thereof.

Referring now in detail to Figures 1 to 5 of the drawings, there is shown a typical and illustrative embodiment of applicants invention. The impression cylinder I comprises a relatively large cylindrical body of the desired diameter which is provided with one or more relatively narrow slots II extending longitudinally of the surface of the cylinder, and communicating with an axially extending cavity I 2 formed in the body of the cylinder. Preferably, the slots II do not extend across the entire length of the cylinder I0, in the case of a relatively long cylinder, but are only a fraction of the length of the cylinder. other and staggered slots being provided for the other longitudinal portions of the cylinder.

The slots II are interiorly beveled and provide a face I3 in which are positioned a series of relatively closely spaced pins I4 which project from the beveled face and serve to impale the various thicknesses of sheet packing I5, I6 and I1, these pins being located on the leading edge of the slot II so as to secure the trailing edge of the sheets I5, I6 and I1. Thus, the structure shown in Figures 1, 4 and 5 is adapted to rotate in a clockwise direction. A jaw member extending throughout the length of each slot II is provided to clamp the trailing edges of the sheets against the face I3, and this jaw member is provided with apertures to lit over the pins I4, and is also formed with a serrated face 2I to increase its grip on the sheets. This jaw conveniently comprises a trough-like member 23, the outer edge of which is reversely turned to provide the jaw portion 25, and this trough member 23 is provided with integral ends 26 by which it may be pivotally mounted for clamping and unclamping movement. One of the ends 26 is also formed with slight recesses 21 near its outer edge which is adapted to be engaged by the nose 28 of a relatively stiff parti-cylindrical leaf spring 29 secured to the body of 'the cylinder I0 by means of the screws 30 within an annular channel 3I. This spring cooperates with the end 26 of the troughlike member soV as to hold the jaw firmly in clamped or unclamped position. The ends 26 are also p'rovided with sockets 33 into which a bar or other jaw operating member may be inserted for clamping or unclamping the jaw.

The means for clamping and stretching the leading edges of the tympan sheets comprise a pair of slotted reel rods extending the length of the slot II and positioned within the cavity I2, and these reel rods 40 and 4I are rotatably mounted by means of their journal ends 42 parallel to the axis of the cylinder I0. At one end of the cylinder the reel rod is mounted in a journal formed in the cylinder end casting while the other ends of the slotted rollers are mounted in a bore at the end of a small rod 45 slidably secured in alined apertures in the inwardly projecting lugs 41, 48. Rods 45 are moved inwardly and outwardly into, and held in, roller journalling position by means of the bent rods 49 which are secured in place and adjusted by means of the nuts 50 which clamp the external end of rods 49 to the mounting plate 5I which is secured over an end hole 52 in the cylinder,plate 5I being held to the cylinder by means of screws 53,. End hole 52 also serves as a hand hole through which the reel rods may be inserted and removed from the cylinder.

For rotating the reel rods 40 and 4I, each of them is provided with a gear 56 secured to the end of the rod nearest the cylinder end and meshing with a gear 51 carried by a rotatable stud 58 journalled in the cylinder end and provided with a squared outer end 59. Studs 5l are also provided with ratchets 6I fast thereto and cooperating with the double spring pawls 52 which prevent unwinding of the reel rods.

The trough-like jaw member 23 is pivotally mounted at one end by means of a sleeve 64 surrounding stud 58. and journalled within the bore 65 in the cylinder end wall, while 'at the other end, jaw member 23 is pivoted on the reduced cylindrical end 68 of rod 69 which is slidable in lugs 41 and 48 and is pushed into operative-position by means of the bent push rod 10 in the same manner as with bar 45 and rod 49. The end walls 26 of the trough-like jaw member 23 are provided with elongated apertures which fit over the ends of the reel rod 40, the elongation of these apertures permitting the pivotal movement of the jaw member for the clamping and unclamping of the trailing edge of the tympan sheets.

As is usual, the slotted reel rods 40 and 4I lare provided with longitudinally extending slots into which the end of the tympan sheet may be inserted before the reel rods are rotated to tighten and stretch the tympan sheets, and preferably the tympan sheet is wrapped at least a full turn around these reel rods so that it may be securely held without slipping.

As shown in Figure 5, the direction of rotation of the impression cylinder III is indicated by the arrow, and the impression cylinder is customarily clothed with three sheets of packing, I5, I6 and I1. The trailing edge of these sheets is impaled on the pins I4 and thereafter the Jaw 25 is-sprung to closed position so as to tightly clamp these sheet ends between the teeth 2l and the beveled face I3. Thereafter, the underlying sheet of packing I5 is smoothed out on the cylinder surface, and the free end is inserted in the gap II, and into the slot 80 and reel rod 4I.

Thereafter, reel rod 4I is rotated in a. clockwise.

direction until the sheet I5 is tightly stretched and securely held. The intermediate sheet or sheets of packing I6 are then smoothed out and leftwith their leading edges free, after which the outermost sheet of packing I1 is smoothed and its free end is inserted into the gap II and then into the slot 80 and reel rod 40. Reel rod 40 is then rotated in a counter-clockwise direction to rmly secure and stretch the outer sheet of packing I1. The rods 40 and 4I are rotated until the packing sheets I5, I6 and I1 are sufilciently stretched, and from time to time these rods 40 and 4I must be tightened to compensate for the stretch of the packing sheets which takes place during continued printing.

I have found that with the .conventional type of impression cylinder as illustratively shown in Fig. 6 (in which the several sheets of packing material I5, I6 and I1 are firmly clamped at their leading edge, while the trailing ends of the sheets I5 and I1 are connected to the reel rods, and the trailing end of the intermediate sheet or sheets I6 is unattached) that the sheet material creeps as it is subjected to the relatively heavy pressure between the printing and impression through which the sheet stretching means' are cylinders, and this creep or elongation occurs lin that portion of the packing material which has been subjected to the pressure of printing, thereby gradually pulling the intermediate sheet I6 ahead of the remaining sheets and tending to accumulate an excess of thesheet I6 near its leading edge and soon resulting in the formation of a wrinkle inthis intermediate sheet I6.

By the present invention (as shown in Figure any stretch which occurs in the intermediate sheet. I6 is opposed by the rm clamp on the 1ntermediate and other sheets at their trailing edges with the result that this usual tendency to 'wrinkle smooths out the intermediate sheet I6 and keeps the tympan in good printing condition.

Although all of the advantages of the present invention are achieved only by rotating the impression cylinder so that the packing sheets are securely clamped at theirtrailing edge, certain of the important advantages are achieved and the other improvements are useful in connection with impression cylinders having the leading edge of the packing sheet securely clamped.

The invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims without departing fromthe principles of the invention and without sacrificing its chief advan tages.

What I claim is:

1. In a tympan cylinder for rotary printing presses, the combination of a hollow cylinder body having a longitudinal slot therein to receive a tympan sheet end, a rotatable member within the cylinder body to stretch the sheet and means for journalling the rotary member including an axially movable bearing member, a rigid member extending therefrom, and means for securing the rigid member to the cylinder. v

2. In a tympan cylinder for rotary printing presses, the combination of a hollow cylinder body having a longitudinal slot therein to receive a tympan sheet end, a rotatable member within the cylinder body to stretch the sheet and means for journalling the rotary member including an axially movable bearing member having an extension'thereon, and means for securing the extension to one of the cylinder ends.

3. In a tympan cylinder for rotary printing presses, the combination of a hollow cylinder body having a longitudinal slot therein to receive a tympan sheet end, a rotatable member within the cylinder body to stretch the sheet and means for journalling the rotary member including a bearing member held against all but axial movement, a rod attached thereto and means for securing the rod to the cylinder end to hold the bearing against axial movement, said cylinder end being apertred to permit removal of the bearing, rod and rotatable member.

4. In a tympan cylinder for rotary printing presses, the combination of a cylinder body havingA a rlarrow slot therein opening into a larger, axially/ extending cavity in the cylinder body, a sheet clamping jaw cooperating with one edge of the slot to secure the tympan, a rotatable sheet stretching means adjacent said slot, and a trough-like jaw body on which the jaw ls mounted and within which the sheet stretchingv means is positioned, said jaw body being pivoted below the sheet stretching means and being provided at its ends with elongated apertures joui-nailed. I

5. In a tympan cylinder for rotary printing presses; the combination of a 'cylinder body having a narrow slot therein opening into a larger, axially extendingcavity in the cylinder body, a

\-sheet clamping Jaw cooperating with Ione edge of the slotto secure the tympan, a rotatable sheet stretching means adjacent said slot, land a trough-like jaw body on which the jaw is mounted and within which thesheet stretching means is positioned, said jaw body being pivoted below the sheet stretching means and being provided at 'its ends with elongated apertures through which the sheet stretchingmeans are journalled, and means for journalling said sheet stretching means and jaw body each including an axially movable bearing member having an extension thereon and means for securing the extension to one of the cylinder ends.

6. In a tympan cylinder for rotary printing presses, the combination of a cylinder body having a narrow slot therein opening into a larger, axially extending cavity in the cylinder body, a sheet clamping jaw cooperating with one'edge of the slot to secure thetympan, a rotatable sheet stretching means adjacent said slot, and a trough-like jaw body on which the jaw is mounted and Within which the sheet stretching means is positioned, said jaw body being pivoted below the sheet stretching means and being provided at its ends with elongated apertures through which the sheet stretching means are journalled,

. rod attached thereto and means for securing the rod to the cylinder and `to hold the bearing against axial movement, said cylinder end being apertured to permit removal of the bearing, rod and rotatable member.

7. A printing press including a printing cylinder and a tympan cylinder rotating therewith, said tympan'cylinder having a slotted cylinder body, a jaw at the leading edge of a slot in the tympan cylinder body to securely hold a plurality of sheets of packing by the trailing edges, a plurality of sheet tightening and gripping members in a slot to engage and tighten the leading edges of a plurality of sheets of packing and a sheet of packing beneath the outermost sheet unattached at its leading edge.

8. A printing press including a printing cylinder and a tympan cylinder rotating therewith, said tympan' cylinder having a slotted,cyl inder body, a jaw at the leading edge of a slot in the tympan cylinder body to securely hold an under sheet of'packing by the trailing end, a sheet tightening and gripping member in a slot to engage and tighten the leading end of an outer sheet of packing, said under sheet of packing, beneath the outermost sheet, having its leading end unattached.

9. A printing press including a printing cylinder and a tympan cylinder rotating therewith, said tympan cylinder having a plurality of sheets of packing clothing the tympan cylinder and secured at their trailing edges to the tympan cylinder, one of said sheets beneath the outermost sheet being free of the tympan cylinder at its leading edge, and means at the leading edge for tightening and securely holding the outermost sheet.

l0. A printing press including a printing cylinder and a tympan cylinder rotating therewith. remaining sheets beneath the outermost sheet said tympan cylinder having a plurality of sheets being free of the tympan cylinder at their leadof packing clothing the tympan cylinder and ing edges, and means at the leading edge for secured at their trailing edges to the tympan tightening and securely holding the outermost cylinder, means at the leading edge for tighten- 5 sheet.

ing and securely holding one of the sheets be- CURTIS S. CRAFTS. neath the outermost sheet, at least one of the 

